Securing of reinforcing strips

ABSTRACT

An arrangement and method for reinforcing a structural component utilizes an elongated strip or lamina which is applied to the surface of the structural component and which has at least one end which submerges into a recess in the surface of the component and is anchored in that recess. This has been found to greatly increase the reinforcing effect of the strip on the structure.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an arrangement for reinforcement at alongitudinally and/or areally extending structure or structuralcomponent by means of at least one lamina-like reinforcement disposed onthe structure or structural component or masonry, slacked orprestressed, a structural component provided for support functions, aswell as a method for reinforcing a structure or structural component.

For many years research and practice has been engaged in the subsequentreinforcement of structures, such as in particular ferroconcretestructures and masonry by applying additional reinforcement. Thebeginnings of this technique are described in J. Bresson, "Nouvellesrecherches et applications concernant l'utilisation des collages dansles structures. Beton plaque.", Annales ITBTP No. 278 (1971), SerieBeton, Beton arme No. 116, and go back to the 1960s. Bresson directedhis efforts in particular to the research of the composite tension inthe region of the anchorages of steel laminae affixed by adhesion.

For approximately the past twenty years, existing structures, such asferroconcrete structures, such as for example bridges, floor and ceilingplates, longitudinal girders and the like, but also nonreinforcedmasonry, can consequently be reinforced through subsequent affixing byadhesion of steel laminae.

The reinforcing of concrete structures and masonry by affixing steellaminae with, for example, epoxy resin adhesives, can be considered tobe standard technique at this time. There are a variety of reasons whichmake reinforcement necessary:

increase of load capacity,

change of static systems by removing, for example, bearing elements suchas supports, or their support functions are reduced,

reinforcement of structural components endangered by fatigue,

increase of rigidity,

damage of bearing systems or renovation of existing structures and ofmasonry, as well as

faulty calculation or workmanship of the structures.

Subsequent reinforcement with steel laminae affixed by adhesion havebeen found to be useful on numerous structures such as is described forexample in the following literature citations: Ladner, M., Weder, Ch.:"Geklebte Bewehrung im Stahlbetonbau" {Adhered armouring inferroconcrete construction}, EMPA Dubendorf, Bericht No. 206 (1981);"Verstarkung von Tragkonstruktionen mit geklebter Armierung"{Reinforcement of bearing structures with adhered armouring}, Schweiz.Bauzeitung, Sonderdruck aus dem 92. Jahrgang, No. 10 (1974); "DieSanierung der Gizenenbrucke uber Muota" {Renovation of the Gizen bridgeacross the Muota}, Schweiz. Ingenieur & Architekt, Sonderdruck aus Heft41 (1980).

However, these reinforcement methods entail disadvantages. Steel laminaecan only be supplied in short lengths which only allows application ofrelatively short laminae. Consequently, laminar stacks become necessaryand thus potential weak points, cannot be avoided. The awkward handlingof heavy steel laminae on the site can in addition lead to especiallydifficult problems in implementation techniques in the case of highstructures or those difficult to access. Moreover, in the case of steel,even with careful corrosion protection treatment, the danger of lateralconcealed rusting of the laminae, or the corrosion on the interfacebetween steel and concrete exists which can lead to the detachment andthus the loss of reinforcement.

Accordingly, it was suggested in the publication by U. Meier,"Bruckensanierungen mit Hochleistungs-Faserverbundwerkstoffen" {Bridgerenovation with high-performance fiber composites}, Material+Technik,Vol. 15, No. 4 (1987), and in the dissertation by H. P. Kaiser, Diss.ETH No. 8918 of the ETH Zurich (1989) to replace the steel laminae bycarbon-fiber reinforced epoxy resin laminae. Laminae comprising thismaterial are distinguished by a low bulk density, very high strength,excellent fatigue properties and outstanding corrosion resistance. It isthus possible to use, instead of the heavy steel laminae, light, thincarbon-fiber reinforced synthetic material laminae which can betransported virtually continuously in the rolled-up state to theconstruction site. It was found in practical determinations thatcarbon-fiber laminae of 0.5 mm thickness are capable of absorbing atension force which corresponds to the yield force of a 3 mm thick FE360steel lamina.

The stated carbon-fiber laminae have been found to be highly useful evenwhen used for reinforcement of masonry in seismically hazardous zones.In Bericht {Report} 229 of the Eidgenossische Materialprufungs- undForschungsanstalt (EMPA) {Swiss material testing and researchinstitution}, Dubendorf, by G. Schwegler with the title "Verstarken vonMauerwerk mit Faservebundwerkstoffen in seismisch gefahrdeten Zonen"{Reinforcement of masonry with fiber composites in seismically hazardouszones} it is in particular suggested to reinforce existing masonry shearwalls or walls in the facade region subsequently with fiber compositelaminae. Therewith masonry can be decisively reinforced with respect toshearing and tension strength, compared to nonarmoured masonry. It isfor example suggested therein to affix by adhesion! the reinforcementlaminae diagonally and crosswise on a shear wall, such as a facade wall,and it was found that for increasing the shearing resistance theterminal lamina anchoring, for example in concrete plates, is critical.

Particular attention must be paid in all described cases to the shearingfractures formation in the concrete or the masonry, respectively.Shearing fractures lead to an offset on the reinforced surface which, asa rule, leads to the peeling or detaching of the reinforcement laminae.The shearing fracture formation is thus also a significant assessmentcriterion with respect to the load capacity of the nonreinforcedstructural component as well as also a potential detachment danger ofthe subsequently applied reinforcement laminae.

The International Patent Application WO93/20 296 describes a method bymeans of which structural components intended for bearing functions arereinforced against shearing forces thereby that the above citedreinforcement laminae are each pressed by means of clamping elements inthe terminal region margin onto the structure in order to prevent theirdetachment. The laminae are disposed such that the distance from thelamina end to the support or the concrete plates disposed terminally atshearing walls is as small as possible. The anchoring zone must bedimensioned such that the lamina tension force can be anchored and thetransfer of the force to a support or to the margin of concrete platesof a shearing wall is ensured.

But it was found in practice that anchoring the reinforcement laminae inthe region of the supports is not always possible due to concrete beamhaunches and shoulders which leads to an increase of the distance. Evenwhen reinforcing shearing walls it is most often difficult and expensiveto anchor the reinforcement laminae in the concrete plates disposed onthese walls above and below. Furthermore, for reasons of handling at theconstruction sites it is advantageous if reinforcement laminae do notneed to be excessively long which results automatically if, for example,when reinforcing bridges reinforcement laminae must each extend fromsupport to support.

SUMMARY OF THE INVENTION

It is therefore a task of the present invention to disclose how, withshortened anchoring lengths on reinforcement laminae, a largely constantreinforcement on structures can be achieved.

What is suggested is an arrangement for reinforcement on alongitudinally extending and/or areal structure or structural componentby means of at least one lamina-like reinforcement disposed slacked orunder prestress on the structure or structural component, whereinaccording to the invention the at least one lamina serving forreinforcement is anchored at least on one end extending into thestructure or structural component.

It is therein suggested that at least the one lamina-end, preferably atleast nearly continuously arched, is deflected for extending into thestructure or masonry in order to be anchored in the structure ormasonry.

In this way it is possible to attain, even with short anchoring lengths,a similar or nearly identical reinforcement on a structure or masonry aswith relatively long practically from support to support and ananchoring of the lamina ends is possible in the region of the supportswithout encountering difficulties. Studies which will be discussed infurther detail in the following with reference to the enclosed figureshave shown that reinforcement laminae which are only disposed over arelatively short anchoring length with regard to the load introductionon the structure to be reinforced and which, according to the invention,have been anchored by projecting into the structural component, yield anearly identical reinforcement on the structure as when thecorresponding lamina end is anchored up to the region of the support.

It is understood that the suggested arrangement or anchoring,respectively, according to the invention of a lamina end such that itprojects into the structure or masonry, respectively, is, suitable forany known reinforcement laminae, such as for example steel laminae,laminae reinforced by fiber glass or carbon fibers, for example producedwith epoxy resins or polyester resins, extruded reinforcement laminaecomprising a thermoplast, etc.

The at least one end of the reinforcement lamina or also both ends ofthe reinforcement lamina are preferably set into the structure extendingat a constant arch wherein each of the set-in end can be covered bymeans of concrete and/or a polymer-reinforced material, such as inparticular an adhesive agent. In the case of, for example, carbon-fiberreinforced epoxy resins, it is advantageous to use an epoxy mortar or anepoxy resin-reinforced concrete polymer, respectively, in order toanchor or cover, respectively, the end of the lamina set into themasonry or the concrete, respectively.

It is understood that it is also possible to press the lamina endprojecting into the masonry or concrete structure, respectively, assuggested in WO93/20296, with a plate, lamina or truss-chord-likeelement against the structure or the structural component, respectively,in order to attain in this way a further reinforcement against occurringshearing forces. For this purpose is also suitable, for example, a wedgecovering the lamina end.

Instead of these pressing means it is also possible to anchor the laminaend additionally by means of prestressed or non-prestressed mechanicalfastening means, such as in particular bolts, rivets, pins, loops andthe like in the structure or the structural component, respectively, orthe masonry.

The arrangement suggested according to the invention is suitable for astructure or a structural component, respectively, intended for bearingfunctions, which is reinforced with one or several reinforcement laminaeagainst occurring shearing forces. But also for the reinforcement of anystructure or a masonry by means of one or several reinforcement laminaeit is advantageous to anchor the lamina ends, such as is suggestedaccording to the invention, such that it extends into the structure orstructural component, respectively, or the masonry. It is for examplepossible when reinforcing masonry in seismically hazardous zones bymeans of GFK laminae to anchor the lamina ends such that they extendinto the masonry, which makes superfluous the necessity to end for thepurpose of anchorage the laminae into the concrete plates or coverplates, respectively, disposed terminally with respect to the masonry,which represents a significant simplification when applying suchreinforcement laminae.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, for example with reference to the enclosed figures,the invention will be described in further detail:

In the Drawings:

FIG. 1 is a schematic longitudinal section of a concrete bridgereinforced by means of a reinforcement lamina,

FIG. 2 is a lateral plan view of a masonry or a shearing wall reinforcedby means of reinforcement laminae, suitable for example for aseismically hazardous region,

FIG. 3 is a schematic longitudinal section of the arrangement accordingto the invention and anchoring of a lamina end such that it extends intothe masonry or structure, respectively,

FIGS. 4a and 4b depict schematically and in longitudinal and transversesection respectively a concrete girder or an experimental arrangement,by means of which the terminal anchoring according to the invention iscompared to a conventionally anchored lamina end,

FIGS. 5a and 5b are respective bottom and detail views of anexperimental arrangement with the concrete girder from FIG. 4 with areinforcement lamina adhered conventionally,

FIGS. 6a and 6b are analogous views to FIGS. 5a and 5b, showing anexperimental arrangement as in FIGS. 4 and 5, however with an extendedlamina end,

FIGS. 7a, 7b and 7c are respective bottom, detail and sectional views ofthe same experimental arrangement as in FIGS. 4 to 6, however with onelamina end, such as suggested according to the invention, anchored suchthat it extends into the concrete girder,

FIGS. 8 is a diagram the load deflection in the three experimentalarrangements according to FIGS. 5, 6 and 7,

FIGS. 9a and 9b are graphs illustrating lamina extension at the laminaend at different force stages and in the girder center in theexperimental arrangement according to FIG. 5,

FIGS. 10a and 10b are graphs illustrating extension at the lamina end atdifferent forces stages and in the in the experimental arrangementaccording to FIG. 6,

FIGS. 11a and 11b are graphs illustrating extension at the lamina end atdifferent force stages and in the girder center in the experimentalarrangement according to the invention according to FIG. 7,

FIGS. 12a and 12b show schematically in longitudinal section and planviews respectively a method for anchoring according to the invention, alamina end,

FIGS. 13a and 13b are respective longitudinal section and top views ofthe disposition of an end edge on a lamina end anchored according to theinvention,

FIGS. 14a and 14b shows conjunction with a concrete haunch in respectivelongitudinal section views the problems of the disposition of areinforcement lamina and the corresponding solution according to theinvention, and

FIG. 15 is a further structural arrangement in longitudinal section,which is reinforced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1, illustrates, schematically and in longitudinal section areinforced concrete or ferroconcrete bridge 1, comprising a concreteplate 3 which is supported or held, respectively, by two piers 5 at theparticular supports 7. Due to ageing this concrete bridge has beenreinforced by means of a reinforcement lamina 10 disposed between thetwo supports 7. The reinforcement lamina 10 extends between the twosupports 7 and is affixed by adhesion over its entire length, forexample with an epoxy resin adhesive agent, wherein also in region A'the lamina, as is conventionally customary, is adhered terminally on theconcrete plate 3. As suggested in WO 93/20296, it is possibleadditionally to anchor or press the lamina ends against the concreteplate 3 by means of additional truss-chords or steel plates.

FIG. 2 depicts a shearing wall 11 of a building, which is located in aseismically hazardous area. The masonry 13 is reinforced with laterallyaffixed by adhesion! reinforcement laminae 20, wherein the laminae arein conventional manner anchored in the concrete plates or the bottom 15and cover plate 17, disposed terminally below and above the shearingwall 13. The lamina end extends for example in the region A" into theconcrete plate 17 in order to be anchored in it. The production of thisanchoring is expensive and requires large work expenditures.

FIG. 3 depicts the way in which, according to the invention, in regionsA' or A", respectively, the lamina ends can be anchored simpler and moreeffectively. In this way, in region A' the lamina end does not need toextend into the proximity of support 7 and in region A" it is notabsolutely necessary that the lamina end must extend into the concreteplate 17. As is evident in FIG. 3, the lamina end 22 of thereinforcement lamina 10 or 20, respectively, curves and extends into arecess in the surface of the concrete plate 3 or the masonry 13,respectively, and it is correspondingly covered in this region byconcrete or cement mortar, respectively. It is understood that it isalso possible to implement the coverage 23 by means of a polymeradhesive agent, such as for example an epoxy resin mortar or apolyurethane or silicon formation. The optimum selection of the materialto be used is a function, for example, of the material of which thereinforcement lamina is fabricated. The end of the strip-like elongatedlamina terminates at the end of the recess and is thus braced againstthe recess as shown in FIG. 3.

In conjunction with the following figures, it will be shown in thefollowing that by inserting, shown schematically in FIG. 3, the laminaend into the structure or into the masonry, respectively, a decisiveshearing reinforcement on the structure can be achieved even if thelamina length, not as usually required, is selected such that it extendsfrom support to support or from concrete plate to concrete plate. Withthe experimental arrangement described in the following will inparticular be shown that with identical lamina length an increase of thereinforcement can be attained if the lamina end(s) are anchored suchthat it (they) extend(s) into the structure or the structural component,respectively, or the masonry.

FIG. 4a shows in longitudinal section a concrete girder 3 analogous tothat of FIG. 1, which is used for the following experimentalarrangements. Concrete girder 3 rests on supports 7 and comprises asteel armouring 4. The concrete girder 3 has additionally beenreinforced on its under side 8 by means of a CFK lamina 10 wherein theone end 11 of the lamina extends practically up to the correspondingsupport 7', while the opposing lamina end 13 is spaced apart from theother support 7". FIG. 4b shows the concrete girder from FIG. 4a incross section.

The concrete girders shown schematically in FIGS. 4a and 4b weresubjected to bending tests in conjunction with different experimentalarrangements, wherein at the two sites 15 indicated by an arrow, a forceF was introduced.

The experimental arrangement, shown in FIG. 5a, depicts thereinforcement lamina in plan view from below onto the concrete girder 3to be reinforced, wherein the one lamina end 11 extends up to support 7'while the opposing lamina end 13' extends by a distance beyond thecorresponding point of force introduction 15". The dimensioning of theexperimental arrangement is shown in the representation of FIG. 5a,wherein the lamina end 13' extends correspondingly by 20 cm beyond thepoint of force introduction 15". In FIG. 5b are depicted schematicallythe measuring points 29 which are to be provided at the lamina end 13'for determining the forces occurring or the extension occurring,respectively. Site 24 in FIG. 5a marks the center of the concrete girder3 at which also a measuring site is disposed.

In order to prevent failure of the lamina 10 in the region of end 11,further a (not shown) pressing plate is provided. The lamina end 13' isanchored affixed by adhesion! in conventional manner on the underside ofthe concrete girder.

FIGS. 6a and 6b show an analogous experimental arrangement wherein,however, the lamina end 13" extends by 30 cm beyond the correspondingpoint of force introduction 15", and thus extends closer to thecorresponding support 7". Again, in the region of end 13" severalmeasuring sites are provided, as well as also centrally at site 24 onthe concrete girder 3.

In FIG. 7 is depicted an experimental arrangement, wherein now thelamina end 13'" is anchored such that it extends into the structuralcomponent which is shown schematically in longitudinal section of FIG.7c. The lamina end 13'" extends therein again only by 20 cm beyond thecorresponding point of force introduction 15", thus is spaced apart bymore than 10 cm from the corresponding support 7", compared to theexperimental arrangement according to FIG. 6a and 6b. The anchorage ofthe lamina end 13'" extends along a distance of 10 cm, wherein the FIG.7c the continuously bent end piece 13a'" extending into the concretegirder 3 is shown schematically in longitudinal section. Over the laminain region 23 in the anchoring zone of the end segment 13a'" an epoxyresin mortar was applied. Again in FIG. 7b schematically severalmeasuring sites 29 are depicted, which have been disposed on lamina 10.Also at site 24 in the center of the concrete girder 3 a measuring sitewas disposed on the reinforcement lamina 10.

FIG. 8 shows in the form of a diagram the load deflection of theexperimental girders measured in the center of the girder with theexperimental arrangement used according to FIGS. 5, 6 and 7. Thedeflection δ (mm) is shown as a function of the force (KN) introduced atsites 15, wherein segregated by extension it is shown for the threeexperimental arrangements of FIGS. 5, 6 and 7.

In each of the Figures a of FIGS. 9, 10 and 11 are shown the laminaeextensions at the lamina end at different force stages for the threeexperimental arrangements of FIGS. 5, 6 and 7 as well as in theparticular Figures b the extensions in the girder center.

In the following Table 1 for the three experimental arrangements themeasured girder resistances the mean lamina tension in the girdercenter, as well as the type of failure of the girder are listed.

    ______________________________________    Girder  Fmax kNm!   σL (F)  N/mm.sup.2 ! *)                                     Failure    ______________________________________    FIG. 5  65          456 (60)     lamina start    FIG. 6  65          628 (65)     lamina start    FIG. 7  75          1'063 (75)   lamina start    ______________________________________     *) mean lamina tension in girder center

Discussion of the results or of the diagrams, respectively, according toFIGS. 8 to 11 as well as of Table 1:

The maximum load, and in particular the maximum lamina extension, in theexperimental arrangement according to the invention according to FIG. 7could be increased significantly relative to the girders of theexperimental arrangements 5 and 6. In spite of different anchoringlengths in the region of ends 13' and 13", the girders according toFIGS. 5 and 6 exhibit similar behavior. In the central girder region thesame extensions are registered. {Each of} The laminae shear off thelamina end when they reach yield load.

The lamina of the girder according to the arrangement suggestedaccording to the invention in FIG. 7 is set at one end 13'" into theconcrete girder 3 and covered with adhesive agent 23. The maximum laminaextensions could be markedly increased relative to the experimentsdescribed above in connection with the arrangements according to FIGS. 5and 6. This behavior can presumably be explained as follows:

Deflection of the resulting tension components perpendicularly to theaffixed lamina. Therewith the lamina is pressed on generatingcompression tensions in the concrete. With corresponding ideal andoptimized geometry of the end segment 13a'" extending into girder 3pressing of the lamina onto the girder can be achieved, which iscomparable to the effect of the transverse tension described in theInternational Patent Application WO 93/20296.

The adhesive agent on the lamina or a pressing wedge according to FIG. 3or the subsequent FIGS. 13a and b prevents the untimely detachment ofthe lamina end caused by the perpendicular tension component directedaway from the girder.

By means of the experimental arrangements in FIGS. 5 to 7 thus it canemphatically be shown that through the terminal anchoring according tothe invention extending into the structure, of the reinforcement laminaea significantly increased reinforcement on the structure can be attainedcompared to a reinforcement lamina of equal or greater length, whosecorresponding end is not anchored according to the invention so as toextend into the structure but rather, as known from prior art, isaffixed by adhesion! along a significantly longer anchoring path ontothe structure or is anchored in contact on the latter, respectively.

In FIGS. 12a and 12b a method is depicted schematically of the way inwhich the terminal anchoring according to the invention of areinforcement lamina 10 is possible relatively simply. As a rule,grinding-in, milling-in or grinding-off into the structure is notpossible so that, as shown in FIGS. 12a and 12b, it is suggested toaccomplish the terminal extension into the structure of thereinforcement lamina end 22 by means of so-called stepped-off corebores. Thus in the terminal region so-called core bores 31 arestepped-off by means of for example a conventional drilling machine intothe concrete 3 to be reinforced, wherein the first bore removed from thelamina end has only a low depth while the last core bore 31 in theregion of the lamina end has a great depth. Such core bores can have,for example, a hole diameter of 10 or more cm, depending on the width ofthe reinforcement lamina 10 to be anchored. After the disposition of thelamina end 22 such that it extends into the structure, an anchoringwedge 23 can again be placed, as described in FIG. 3.

Such anchoring wedge is also depicted in FIGS. 13a and 13b, wherein nowadditional fastening means 33 are disposed, which can be, for example,screws, bolts, loops etc. By means of these securing means 33 theanchoring effect of the wedge 23 onto the lamina end 22 is additionallyaugmented. FIG. 13a shows the wedge 23 in longitudinal section whileFIG. 13b represents a top view onto wedge 23.

In FIGS. 14a and 14b a concrete structure 32 is shown such as forexample a bearing structure in galleries or tooling halls, in whichstructure the ceiling plate 35 and the side wall 37 are connected withone another in the corner region across a so-called haunch 39. If theunderside of the ceiling 35 is to be reinforced by means of areinforcement lamina 10, it is clearly evident in FIG. 14a that theanchoring of the lamina end 13 in the region of the haunch isunfavorable since upon the occurrence of tension forces acting! onto thereinforcement lamina 10 the latter becomes detached in the corner region36.

As shown in FIG. 14b, for this reason it is suggested according to theinvention to anchor the reinforcement lamina 34 or its end 22,respectively, in the comer region 36 in such a way that it extends intothe concrete ceiling 35. When the concrete ceiling 35 is under load, thetensile stress component due to the bending moment onto the lamina inthe end region of the lamina is deflected into the ceiling whichprevents the lamina end 22 from becoming detached.

Lastly, FIG. 15 depicts a further structural arrangement, for exampleagain a bearing structure, comprising a concrete ceiling 41 as well as apartition wall or a longitudinal pier 43, wherein again the ceiling 41is reinforced by means of a reinforcement lamina 10. In the comer region45, between ceiling 41 and pier 43, is anchored according to theinvention the lamina end 22 such that it extends into the ceiling.

In conjunction with the auxiliary line 53 drawn in FIG. 15 the course ofthe bending moment with respect to the structural component or to thesystem center plane 47 extending through the ceiling is shown. Thereinis clearly evident the passage through a zero point at distance x fromthe pier 43 near the corner region 45 and a subsequent strong increase.Through the anchoring according to the invention of the lamina end 22 atinterval range x where no tension force occurs, it is already possiblestarting at the zero point to absorb fully the subsequently generatedtension stress through the reinforcement lamina 10. In the event thatthe reinforcement lamina 10, affixed by adhesion! as usual, wereanchored in the corner region 45, an absorption of the generated tensionstress would only be possible at a distance greater than! x from thecorner region 45, whereby the danger of shearing-off of the lamina 10from the concrete ceiling 41 is given.

FIGS. 1 to 15 serve only for the further explanation and illustration ofthe concept according to the invention and it is understood that theterminal anchoring suggested according to the invention, ofreinforcement laminae can be selected to be any desired one. Thematerial used for the reinforcement laminae can also be any desiredmaterial, thus a lamina can be comprised for example of sheet iron,steel, aluminum, a reinforced polymer, such as in particular aGFK-reinforced epoxy resin, etc. Essential to the invention is the factthat a reinforcement lamina applied or affixed on a structure or masonryis anchored so as to extend at least with one end into the structure ormasonry, respectively; whether or not therein a reinforcement wedge isused is not of primary significance and depends on the requirements andthe locality.

We claim:
 1. An arrangement for reinforcing a structural componenthaving a surface, comprising, in combination with the structuralcomponent, and elongated lamina strip adhered to the surface and havingopposite ends;the surface of the structural component having a recessadjacent at least one of the ends of the lamina; and at least one end ofthe lamina extending into the recess and terminating at an end of therecess for reinforcing the structural component.
 2. An arrangementaccording to claim 1, including adhesive filler filling the recess andcovering a portion of the end of the lamina extending into the recess.3. An arrangement according to claim 2, wherein the recess curves intothe surface of the structural component and has an end which issubstantially transverse to the surface, the lamina curving so that theend of the lamina curves into the recess and engages the end of therecess.
 4. An arrangement according to claim 1, wherein the recesscurves into the surface of the structural component and has an end whichis substantially transverse to the surface, the lamina curving so thatthe end of the lamina curves into the recess and engages the end of therecess.
 5. An arrangement according to claim 1, when the lamina iscurved so that the end of the lamina curves into the recess, the end ofthe lamina being covered in the recess by a material selected from thegroup consisting of: concrete, cement, mortar or polymer-reinforcedadhesive.
 6. An arrangement according to claim 1, wherein the lamina ismade of material selected from the group consisting of: iron, steel,aluminum or fiber-reinforced polymer.
 7. An arrangement according toclaim 6, wherein the recess curves into the surface of the structuralcomponent and has an end which is substantially transverse to thesurface, the lamina curving so that the end of the lamina curves intothe recess and engages the end of the recess.
 8. An arrangementaccording to claim 1, including means for pressing the end of the laminainto the recess.
 9. An arrangement according to claim 8, wherein themeans for pressing the end of the lamina is selected from the groupconsisting of: a wedge, a plate, an additional lamina or a truss-chord.10. A method of reinforcing a structural component having a surface,comprising:providing a recess in the surface having a curved entryportion and an end which is substantially perpendicular to the surface;adhering an elongated lamina to the surface with an end of the laminaextending over the recess; and bending the lamina end into the recess sothe lamina end is braced against the end of the recess and is bent alongthe curved entry portion of the recess.
 11. A method according to claim10, including covering the end of the lamina which is in the recess withadhesive fixing material.
 12. A method according to claim 11, whereinthe adhesive fixing material is selected from the group consisting of:concrete, cement, mortar and reinforced polymer.
 13. A method accordingto claim 10, including pressing the end of the lamina into the recess bymechanical means.
 14. A method according to claim 13, wherein themechanical means are selected from the group consisting of: a wedge, aplate, a further lamina and a truss-chord.